


Stuck in a...

by Annie D (scaramouche)



Series: Stuck [1]
Category: Marvel Cinematic Universe
Genre: Alpha Steve, Alpha/Beta/Omega Dynamics, Barebacking, Bodily Fluids, Bottom Tony, Breeding Kink, Consent Issues, Getting Together, Happy Ending, Hurt/Comfort, Knotting, M/M, Mating Cycles/Heats/Ruts, Omega Tony, Tony POV, Top Steve, biology made them do it
Language: English
Status: Completed
Published: 2020-03-24
Updated: 2020-04-02
Packaged: 2021-02-28 19:47:45
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 13,005
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23292709
Author URL: https://archiveofourown.org/users/scaramouche/pseuds/Annie%20D
Summary: Steve gets into a serum-enhanced rut. Tony figures that there’d be a long list of people who’d volunteer to help Steve out, but there’s only one person Steve wants.
Relationships: Steve Rogers/Tony Stark
Series: Stuck [1]
Series URL: https://archiveofourown.org/series/1712872
Comments: 195
Kudos: 1750
Collections: Stony*, Tony-involved Omegaverse Fics





	1. Chapter 1

Biology and biochemistry are more Helen and Bruce’s arena, but Tony’s all for expanding his horizons whenever the situation calls for it. The three of them have been in Helen’s lab for almost twelve hours now, with Tony somewhat in the back seat reading textbooks of rut cycle hormone pathways, while the other two run simulations and put Steve’s bloodwork through test upon test upon test.

It’s quite the pickle. It’s even gotten to the point that Tony’s light teasing earlier feels tasteless in retrospect – Tony’d rolled his eyes at the threat of Steve’s falling to his base instincts, because what would Steve do? Yell at litterers and pick fights with people on the internet? But that was yesterday, when the situation seemed no more than a typical alpha-on-the-verge-of-rut case.

“What gets me is that this hasn’t happened before,” Tony says, his vision swimming a little when he looks up from his tablet screen. “Steve fought in a freaking war. How’s that _not_ a stressful situation? He must’ve had a couple of ruts while that was going on.”

“Body chemistries change as we age,” Helen says. “The serum is supposed to keep Steve in peak physical health, but that’s as far as it was intended. Erskine didn’t actually know how it’d perform.”

“And going into the ice could’ve changed something in Steve,” Bruce says. “Goodness knows getting gamma-rayed messed me up.”

Helen nods. “Fact is, we don’t have any bloodwork from back then to compare to. All we have for a baseline are regular, healthy alphas, and so far that’s all that’s panning out.”

“Fight stress,” Tony echoes. It’s the tentative conclusion they’d come to a couple of hours ago, and it sounds no less ridiculous now as it did then. “Captain America, he of let’s-firebomb-a-tank-for-funsies, is under fight stress.”

“Well,” Bruce says, “an alpha rut has a great deal in common with the omega heat, you just need to apply some imagination—”

“It’s not the rut part I’m having a problem with!” Tony exclaims. “It’s just... this is _Steve_. All we did yesterday is save a cruise liner from hijackers, which is hardly world-ending. Or even world-pausing.”

Bruce turns on his swivel stool, away from the multiple screens of his work station, and faces Tony. “You think it’s weird that a rut can put Steve out of commission?”

“Frankly, yeah.” Tony still can’t get the image out of his mind, how when they came back from the mission yesterday Steve was more irritable than usual, snapping at everyone and taking everything seriously (like it was the old days again) and even at one point shoving Thor because he was in the way. Even when critically injured Steve’s preference has always been to play it off and make no big deal of it, which is its own kind of irritating but is at least familiar. Steve made cranky by a fight-enhanced rut is too much of an alpha cliché, and so far removed from who Steve _is_.

Somewhere in the couple of years that they’ve been Avenging together, Tony’s kinda started forgetting that Steve is an alpha at all. Sure, he’s a natural leader, and sure, he’s bossy and gets up in everyone’s business to make sure they’re taking care of themselves, and _sure_ , he’s prone to picking fights when it’s not necessary, but... there’s everything else. He’s patient, he listens, he does any chore anyone asks of him, he admits when he’s made mistakes, and he’s never ever invaded any of Tony’s spaces without invitation, be it spatial or personal.

Losing control to a rut just feels _beneath_ Steve. If Tony ever thought about Steve’s ruts (which he hasn’t) he would’ve assumed that Steve handles them the same way he does any of his workouts, i.e. with enthusiasm, efficiency and satisfaction. It’s just another thing that the body needs, and Steve would see to it with the productivity that is typical of him.

“So,” Bruce says thoughtfully, “you’re surprised at this, because Steve’s turned out to be not as strong as you thought he is?”

“No, geez, not that,” Tony says, appalled.

Bruce hums. “Then you’re surprised because he’s only human.”

“Oh, that’s... maybe.” Tony makes a face. That doesn’t feel quite right, because it’s not as though Tony thinks Steve’s without flaws. The man has plenty, which he makes known to Tony every day since they’ve known each other. An out-of-control rut isn’t even a flaw in itself; it’s just inconvenient biology.

“We’re all worried about Steve,” Helen says.

“I’m not worried,” Tony says quickly. He shrinks back when Helen gives him a look, only to change his mind and jut his chin out. “If Steve can survive a building falling on him, he can definitely survive an inconvenient rut.”

“Oh hey.” Bruce leans over to read his cellphone screen. “A message from Steve. He’s asking for Cheryl.”

Tony scowls. “He doesn’t think his room can contain him?”

“That is the subtext,” Bruce says.

“Okay.” Tony nods to himself, and slowly gets up. “You guys keep working. I’ll see to Cheryl.”

Bruce clears his throat. “Actually, he’s asked _me_ —”

“I can handle it,” Tony says firmly. “Get that sedative done.”

Tony’s out of the lab before either of them can argue against it.

+

Steve’s been hiding out in his room since they came back from the cruise liner mission. Natasha and then Thor have been to check on him; Natasha just received a vague answer of Steve’s feeling under the weather, and a couple of hours later Steve told Thor that he’s having an unusually intense rut.

Tony, of course, suggested the obvious as soon as they were informed about the rut. If Steve can’t handle it on his own, they should just get someone into his room to help him out. Thor replied that maybe Steve doesn’t want that because of his increased fight-induced aggression; he’d need a partner who can handle his super strength.

“Are you assuming, or did Steve actually say that?” Tony had asked.

“I am assuming,” Thor admitted. “Your earth biology cycles are so inconvenient. But if I were him, that would be my greatest concern.”

“Or maybe Steve doesn’t want anyone to ‘help’,” Natasha said. “Probably thinks he can just wait it out.”

“That does sound like him,” Tony agreed.

One thing they all agreed on was that no one would go to Steve’s room except Thor. With Steve’s agreement, his room’s been locked from the outside, and only Thor – the only one of them without a secondary sex and also strong enough to keep Steve from leaving – has seen Steve, in order to deliver meals and take blood samples.

That’s about to change, since Tony’s going up to Steve’s room now.

Tony’s not an idiot, of course. He’d made a detour to his workshop first, both to power Cheryl up and collect the necessary accessories.

Bracing himself, Tony knocks on Steve’s door. “Hey Cap,” he says. “Your Uber’s waiting.”

For a handful of seconds, there’s silence. Then Steve’s voice, deep and angry, comes through the door: “What the hell are you doing here?”

“You want to be transferred to Cheryl? I’m transferring you to Cheryl.” Tony looks down at the door latch. “Brace yourself, I’m coming in.”

“No!” Steve shouts. “Tony, no, please, just—”

Tony unclicks the latch and pushes the door open. He pauses on the threshold to take in the scene: the bed a mess, takeout boxes on a table, and one chair smashed up into pieces on the floor. As for the man himself, Steve’s on the floor at the far side of the room, as far away from Tony as he can manage, with the bed a barrier between them.

“Oh,” Steve says, relief coloring his voice. “You’re wearing the suit.”

“Of course I’m wearing the suit.” Tony waves gauntlet-covered hand at Steve. “You think I’m gonna get my omega cooties all over your room? Please.”

Steve makes a sound that, in other circumstances, would probably be a laugh.

Tony steps further into the room, carrying a large canvas bag with him. Steve’s going to need to bring some clothes, toiletries and distractions – maybe a couple of books, not that Tony’s known any alphas who can focus enough through their ruts to read.

He eyes the smashed chair curiously, and starts to say that he hopes that Steve didn’t try to knot the poor chair. But the joke dies in his throat when he registers (via the HUD) the sheer misery on Steve’s face. Steve, whom Tony has never seen sick and never heard complain of any injury no matter how awful, is now huddled by the wall looking like the poster boy for haywire hormone hell. He’s flushed and sweaty as though from a fever, with patches of damp on his hair and the gray cotton shirt he’s wearing.

“Okay,” Tony says instead. “It’s a couple of floors down, so unfortunately you’re gonna have to do the walking yourself.”

“Yeah. Okay.” Steve takes a deep breath, licks his lips, and slowly drags himself to his feet. He doesn’t bother trying to hide the bulge at his crotch, as though he doesn’t even remember that it’s there.

Concern distracts Tony for a second, but he remembers himself. He goes to the closet, randomly picking at drawers and grabbing whatever can be useful. Steve sees what he’s doing and putters off to the bathroom to collect other items that he adds to the bag.

“How’s the analysis going?” Steve says hoarsely.

“Three geniuses can’t go wrong,” Tony says. “We’ll get something.”

“I know you will,” Steve says.

“Are you just saying that, or are you expecting to ride it out on your own?”

“If you don’t want me to ride it out on my own, you’ll just have to find a solution, won’t you?” Steve counters.

Tony huffs an agreement.

As they pack, Tony has JARVIS scan for Steve’s vitals, which he compares to the last set of Thor’s reading. Steve’s temperature is holding steady but his motor control is not looking too good.

“It’s really never been like this before?” Tony asks. “Sorry, I know it’s personal—”

“Never.” Steve struggles as he swallows, as though his throat’s dry as sandpaper. “Never been like this. Never felt like…” He coughs. “There was a – yesterday, when we were fighting the hijackers. I hurt someone really badly, didn’t I?”

“It’s fine, he’s fine,” Tony says quickly.

“No, a lot of it’s hazy, but I remember that, I remember using the shield—”

“Steve.” Tony comes to stand in front of Steve, commanding his attention. Tony’s a little taller than Steve when he’s in the suit, and now it forces Steve to tilt his head back a little to look at him. Steve’s eyes are alarmingly watery, as though 70 years of allergies are catching up on him at once. Still, Tony keeps his voice calm when he says, “Steve, I want you to listen to me. You did lose control a few times yesterday, but Natasha was there to make sure you didn’t take it too far. You did hurt people, but no more than in a usual fight, and you didn’t kill anyone.”

Steve believes him, thank goodness, and accepts it with a nod.

“Let’s get you moved now, yeah?” Tony says.

“Okay.” Steve smiles shakily. “Thank you, Tony.”

“That’s what I’m here for.” Tony adds, in a lighter tone, “I mean, I’m being selfish as well. A super serum alpha in a rut, under the same roof as me? Of course I’m gonna see that up close, like what do you take me for? _Not_ a scientist?”

Steve does laugh then, and it makes Tony feel even more sure that they’ll figure out a way to fix this.

+

Cheryl is a reinforced containment unit meant for use on the Hulk, and is vastly modified and improved (with Bruce’s input) from the glass cell that SHIELD had ages ago. It’s still a cylinder, but is half glass and half titanium alloy, has more leg room, and is fitted with a small bathroom module for extended stays. Not that they ever expected anyone who isn’t Bruce to use it.

Steve makes the whole journey downstairs to Cheryl’s floor under his own power, though his usually picture-perfect posture seems a distant memory as he lumbers his way there. Tony shadows Steve the whole trip, and has JARVIS temporarily lock down all the corridors, stairwells and elevators to prevent anyone from stumbling upon them during this journey.

When they arrive at Cheryl, the unit’s already been powered up – lights, air filtration, security systems, et cetera – and ready for use. Steve drops gracelessly into the cot, and nods a wordless thank you while Tony hands over the extra blanket and pillow.

“You really think you would’ve broken out of the room?” Tony says. “I mean, this is… a step.”

“It’s for the best,” Steve says.

Tony hums a non-agreement as he looks around. There’s only one chair and it’s definitely not strong enough to hold the suit. He did put Steve’s tablet in the bag, so maybe they can watch a movie or something. Tony starts to move for the bag when Steve stops him with a hand on the gauntlet.

“Tony,” Steve says. “I want you to get out of the cell.”

“Here’s a better idea. I was thinking I can get the beanbag from the rec room—” Tony startles when Steve gets a strong-enough grip on the gauntlet and shakes it, the sensation passing through the alloy layers to his arm underneath.

“Tony.” Steve’s sweat-soaked and pallid, but he can still glare. “I don’t want you in here with me.”

“But you can’t smell me,” Tony says. “The suit’s air tight.”

“It is, but I don’t…” Steve’s eyes glaze over for a second. Tony can’t feel it, but the HUD lets him know that the suit’s sensors are registering Steve’s hand moving over the gauntlet, his fingers lingering on the wrist joints.

“I don’t blame you,” Tony says with a nod. “The suit is pretty sexy.”

Steve’s eyes sharpen and he scrambles backward on the cot, panicked and angry. “Tony!”

Tony sighs and takes a step away from Steve. “I just can’t stand you being alone in—”

“How about you think about yourself this time?” Steve snaps.

“You can’t jump me when I’m in the suit. I mean, you can _try_ , but I’m sure—”

“Not fucking funny.”

The swear brings Tony up short. Steve’s one of those guys who uses curses to the best of their impact, and despite the ups and downs of their working relationship (and friendship, Tony likes to think that’s what they have, though he’s never been too good with boundaries in the first place) and all the disagreements they’ve had, Steve’s never cursed at Tony in anger.

Steve’s angry, out of worry and fear. And knowing Steve, he’s frightened for others more than he is for himself.

“Okay,” Tony says, keeping his voice calm and, hopefully, calming.

Tony takes clanking steps all the way out of Cheryl and locks the door behind him. There are three locks, all of them loud as they click-snap shut (they don’t need to, but being dramatic is the Avengers way). That done, Tony comes to stand in front of the glass partition, where he watches as Steve, his eyes shut, takes one heaving breath after another.

Tony doesn’t like it. Sure, there’s not a lot to like in Steve having to be alone as he waits for the brain-twins to find a relaxant that the serum won’t immediately metabolize, but Tony especially doesn’t like that it’s a fever rut that has Steve grounded. Because fever ruts, part and parcel of humanity, are centered on a single, specific goal.

It is, of course, Steve’s right to not knot anyone if he doesn’t want to. But it doesn’t sit right with Tony that no one’s pushed harder on the obvious solution, no matter that everyone here respects Steve and his personal boundaries. No one wants to be that asshole. Not even Tony, for whom this is far, _far_ out of the realm of any sort of joking.

But Steve’s in real, physical pain that Tony would bet good money is worse than it looks, and they have no idea what the serum will do to him if his body doesn’t get what it wants.

Tony has JARVIS pull up his contact list. Just the idea makes him feel queasy, but at least he’ll have tried? This isn’t the kind of thing someone talks about from behind a mask, either.

Tony takes a bracing inhale and commands the suit to open. He steps out of it and onto the floor, and brings his hands up to rub his face as he thinks.

There are options. They’re not ideal options, but they’re still options that are at the very least worth discussing, even if Steve’s ultimate response is a rejection. Now if only Tony were someone who’s tactful and sensitive, but personality transplants are unfortunately not on the table either.

Tony brings his hands down, and jolts.

Steve’s no longer lying on the cot with his eyes closed. While Tony wasn’t looking, Steve got up and walked across the cell, and is now pressed up against the full-length glass panel right in front of Tony. Frankly, Steve is sweat-soaked and disgusting, and a part of Tony’s brain tries to focus on that – Steve Rogers, for once not perfectly, excruciatingly photogenic – because the rest of him has tensed up in sudden acute awareness of a fever rut alpha a handful of feet away from him, staring at him, and with only the reinforced glass wall separating them.

“I asked you to leave,” Steve says. His eyes are wide, alert, almost unblinking.

Tony looks up at the ceiling. “JARVIS, filters working?”

“ _Yes, sir_ ,” JARVIS says from the suit.

“Tony.” Steve’s hands are pressed against the glass, fingers twitching and curling as though trying to find purchase to scratch his way out. “I’d really appreciate it if you leave.”

“You can’t smell me,” Tony says.

“But I can see you.” A strange expression passes over Steve’s face. It’s not an entirely unfamiliar expression – Tony’s seen it in many a hotheaded alpha during his young, swinging days – but it’s really fucking eerie to see it on Steve’s face, even if only for half a second before it changes back to Steve’s now-regular face of exhaustion and misery. “I can still see you, and I’d really…” he swallows, “…rather not.”

Tony looks down. The outline of Steve’s huge erection threatens to burst the seams of his sweatpants. Under Tony’s gaze, Steve’s hips move forward, humping the glass. Pre-come has darkened the cotton material.

As an omega, Tony could be afraid. As Steve’s teammate, Tony could be embarrassed. But here and now, Tony’s only able to worry for Steve, to the edge of franticness. How much worse will it get? He’s fucking Tony Stark, he can find a way to fix anything.

“I know an agency,” Tony says, lifting his gaze back to Steve’s. “They’re very discreet, and their omegas enjoy their work—”

“No,” Steve says.

“You need it.” Tony gestures at Steve’s crotch. “You need to tie.”

A grimace spasms across Steve’s face. “Maybe.”

“Maybe,” Tony echoes, with more sarcasm than is necessary. But his irritation fades at the squeak of Steve’s fingers on the glass, trying to claw and failing. “Okay, okay, okay. I’ve been assuming that there’s no non-Avenger you trust that we can call—”

“No,” Steve barks.

“I could build something for you. Something…” Tony thinks quickly. “Give me a day, maybe less, and I can make something with the right scents, it might trick—”

“No.”

“Thor? Helen should be able to synthesize a hormone masker—”

“Please go,” Steve says weakly.

“Hey, that’s not a ‘no’! You’d consider one of us? If not Thor, then maybe me or Natasha?” Steve flinches, which makes Tony frown. “I mean, Natasha’s better of course, she’s younger and—”

“Can you please just stop!” Steve pauses to heave for breath. “It won’t work.”

Tony frowns. “What won’t work? Tying?”

“Thor. Or Natasha. Or anyone from your agency.”

“How do you know?”

Steve blinks groggily. A bead of sweat trails off one of his eyelashes. “I just know.”

“You don’t. You said it yourself, it’s never been like this before. You can’t know what’ll work and what won’t—”

“I know what it needs.” Steve smiles, small and pained. “I know what I need. I’ve known.”

“You’ve known.” Tony tries to absorb that. “Wait. This is… is this escalation? Have your ruts been getting worse over time?” When Steve scrunches his eyes shut, Tony presses on, “Steve, work with me. Just let me understand, so we can figure this out. I mean, look at you.”

Steve has to expend a great deal of effort to open his eyes. He looks down at himself, and how he’s been trying to rub himself against the glass. He laughs, hoarse and sad and awful, and Tony digs grooves into his palms from where he’s clenching his fists.

“Please,” Tony says gently, “just let me help—”

“What, would you let me knot you?” Steve says mockingly. Tony’s stomach jumps – in surprise and something else – as Steve continues, “Would you let me put my dick in you, over and over, taking you, forcing you, ruining you—”

Steve’s voice breaks, and Tony steps forward without thinking, putting his hands on the glass. “Steve, c’mon, stop that.”

Steve’s eyes widen as he registers Tony’s closeness. A racking shudder passes over Steve’s body, and Tony’s heart clenches from frustration and uselessness.

Everything here is wrong, and not just Steve’s attempt to be crude – maybe in another life it could be hot, but not here, not like this, and not when Steve’s nearly in tears from saying it. The fact is, Steve’s the one who knows all the right words of comfort and sympathy, and is able to connect with almost everyone to make them feel better. Tony’s never been good at that even with the people he cares about; all he can do is offer solutions and make himself scarce, and he can’t even do that now.

“You’d let me fuck you?” Steve says in a low voice. “Because that’s what it takes, Tony.”

“Yes, I’m game.” Tony squares his shoulders and starts opening the cuffs of his shirt. “You need an omega? You’re in luck.”

Steve laughs again, a harsh hacking laugh that chills Tony to the bone. He grins at Tony, and the wildness in his blue eyes are not unlike a man standing on the edge of a precipice.

“I don’t need just _any_ omega,” Steve says. He falls silent, his jaw clenched, and lets the statement hang in the air.

It takes a handful of beats for it to sink into the jumbled worried mess that is Tony’s head. When it does, Tony immediately rejects the obvious meaning, because that’s obviously not what Steve meant, except… Steve is watching him. Steve has pressed his chest to the glass and is staring at Tony’s face expectantly.

“Me,” Tony says in disbelief. “Me? You want me?”

He half-expects Steve to bark a correction, but it doesn’t come. Instead, Steve just keeps looking at him, wary and defiant.

To say that this is a surprise is an understatement. Tony does like Steve, and far more than he ever thought he would when they first met, but they’re still learning each other, still chipping away at all those early assumptions, and still trip on each other’s hotspots when they don’t mean to. Hell, Tony still thinks it’s presumptuous of him to tell other people that Steve’s his friend (though he is, in Tony’s head) because their getting along better over the past year doesn’t automatically mean that Steve would willingly spend off-work time with Tony on his own free will (though Tony would and has done so with Steve).

After all, Steve tries to get along with everybody he needs to work with, even people he doesn’t like. He’s exponentially warmer if he _does_ like you, but Tony sees clearly the difference between how Steve acts around him, compared to the easy, subdued affection Steve shares with Natasha and Sam. It does not follow that Steve wants him.

Actually, Tony reminds himself sharply, it _does_ follow. Tony’s hot, thank you very much, and although he’d assumed Steve never noticed that kind of thing, Tony is attractive enough to hold his own in the ridiculous pin-up crew that is the Avengers. Of course there’s no accounting for Steve wanting him over Natasha, but maybe the guy just has a thing for mature (cough) omegas.

The logic is sound, even if it makes Tony uneasy for reasons there’s no time to analyze at the moment. So he nods, decisive, and says, “Okay. I’m still up for it. Let’s do this.”

He starts for the door, but Steve yells and slams his fists on the glass. Stark engineering means that the glass doesn’t shudder at all, but Tony still freezes and stares up at Steve in shock.

“Don’t you dare,” Steve says.

Tony scowls. “Excuse me?”

“You need to go—”

“Oh my fucking God, Steve,” Tony says, exasperation rising. “You’re hurting, and I can _actually_ do something about it, and you think I’ll walk away? You think I can do that? And here I thought we’d been doing good getting to know each other.”

Steve deflates a little, but only a little. “You’d lie on the wire and let me crawl over you?”

“Don’t be so goddamned dramatic,” Tony says with an eye-roll. “I trust you, okay. Maybe I haven’t made that clear, but it’s true and you’re – of course I’d do this for you.” He smiles, hopeful and willing Steve to believe him. “Let me help you.”

Steve moves his head, a stiff jerk sideways and back that it takes Tony a second to realize is him shaking his head. Tony rears up to keep arguing, but then Steve smiles, a shocking pull of soft fondness that transforms his whole face.

“That’s exactly why you can’t,” Steve says quietly.

Tony swallows past the sudden unexplained thickness in his throat. “You’re not making any sense.”

Steve sighs, and Tony realizes that Steve’s resignation scares him more than his anger. Steve closes his eyes, and when he opens them again, it’s clearly to a decision having been made. “If you let me… I’m going to want more.”

“That’s okay,” Tony says quickly. “As many times as you need.”

“I don’t mean just sex, Tony,” Steve says tiredly. “I mean that I’m sweet on you. I have been, for a while. If I got to be with you like that, it’s going to make me want so much more from you.”

“Sweet…” Tony frowns. “What?”

Steve just gives him a look.

“What?” Tony repeats, in case he didn’t say that loud enough the first time. “I—what?”

Hearing that Steve wants a piece of him is a surprise yet somewhat manageable, but this is an exponential leap. Steve cannot possibly mean that he has feelings for Tony, because Tony hasn’t _done_ anything. He hasn’t been extra nice to Steve or anything like that – well, okay, sure, he kinda has, but that was in the name of friendship, because Steve’s funny and fun to be around the few times that Tony’s managed to get his guard down, and Tony’s maybe secretly wanted Steve to think that Tony’s an okay person and worth being around beyond just the work that they’re doing together.

“I don’t…” Tony stares helplessly at Steve. “I wasn’t even sure if you liked me as a friend.”

Steve’s mouth quirks ruefully. “I like you very much.”

“But that’s because you’re – you’re good, you’re nice to everyone, you—” Tony shakes his head, trying to clear it. “I would’ve noticed something.”

“Didn’t want you to. Wanted to steer away from the cliché.”

“What cliché?”

“That the only reason an alpha would want to be friends with an omega is so they can knot them. You mean more to me than that. You mean more to me than _this_.” Steve gestures at himself, a reminder of his condition. “I can be intense about things. After coming out of the ice, everything feels so fragile. The world feels so fragile. So anything that feels good, that makes me happy, I just want to… keep it.” He curls his fingers into fists against the glass. “I want everything – _everything –_ right off the bat, when that’s not how people work.”

“You’ve been trying to go slow,” Tony says carefully. “When what you really wanted…”

“Is to be yours.” Steve holds Tony’s gaze, as though daring him to look away. “I want to know all of you. I want you to know all of me, and to – to like what you find. I want you to want me back, with all your heart.”

Tony takes a startled step back.

“Yeah,” Steve says with a nod. “It’s a lot. So if you let me knot you, like this, it’ll hurt. Not physically, but I’m sure you get it now. I’m going to want you even more than I do, and I’ll hate myself for putting you in that position. It’s not fair to either of us.”

“This is bullshit,” Tony hears himself whisper.

Steve laughs under his breath. “I hear there are three geniuses working on a sedative, so how about we pin our hopes on that one? And I, uh…I hope that we can still be friends? After all of this is over?”

“Of course, you nincompoop,” Tony says automatically.

“Good.” Steve nods, relieved. “That’s all I want.”

Of course, that _isn’t_ all Steve wants, but Tony isn’t about to rub that in his face. As it is, Tony can only look at Steve with a new, dismaying understanding of his own insufficiency. This is a problem he can’t solve, not when taking care of Steve’s fever would just open him to another kind of hurt. Though Tony’s hands still itch for the door, he can’t do that to Steve.

What if he did, though? What if Tony opened the door and went inside and let Steve’s rut fulfill its need? Better to ask for forgiveness than permission, and all that?

Steve would forgive him, but he wouldn’t forgive himself for letting his base instincts get the best of him, not matter that Tony’s the one who forced his hand. Knowing Steve, he might even leave the Avengers to get away from Tony, and that would be really fucking awful. (Why does Steve even want Tony like… that? He’s loud and a mess and some days only as functional as the work he has in front of him, and Steve’s supposed to have good taste.)

“Do you understand now why I need you to go?” Steve asks.

“Yeah,” Tony says, throat tight. “Yeah, sorry, I—”

“I’m the one who’s sorry,” Steve says immediately. “But it’ll be fine. I’m sure of it.”

Tony’s not sure he’s as confident about that, but he manages a quick, “Okay,” before getting back into the suit. “I’ll keep you posted about the sedative.”

The last thing Tony hears as he leaves the floor is Steve’s soft, “Thank you, Tony.”


	2. Chapter 2

**Notes for the Chapter:**

>  **A/N** : Tony has taken birth control precautions, but this chapter features barebacking, condom breakage, and some play-acting breeding kink.

For the rest of the day Bruce and Helen run a couple more simulations, which culminate in the synthesis and testing of an experimental sedative on a volunteer, i.e. Thor, who may not have ruts, but has a strong enough constitution that anything that can knock him out when he’s high on adrenaline should have some effect on Steve. Theoretically.

Tony isn’t there when they do the tests, but he does hear of their results after the fact.

He’s in the common area, eating dinner with Natasha and Clint, when Bruce comes up to see them.

“There’s really no one else we can test except, well, me,” Bruce says.

“And anything that works on the Hulk would kill Steve outright,” Natasha finishes.

“You take pictures?” Clint says. “Of Thor passed out?”

“Pictures?” Bruce says. “What do you take me for? We took a video.”

“When are you giving Steve the sedative?” Tony asks.

“When Thor wakes up.” Bruce’s sympathetic gaze lingers on Tony for a second, and it is by sheer force of willpower that Tony doesn’t fidget. They’re all worried about Steve; Tony isn’t special. “Clint, you’re helping.”

“I am?” Clint says.

“I need all non-omega hands on standby,” Bruce says. “Don’t leave the building.”

While Clint grumbles and Natasha pokes fun at him for it, Tony looks down at his plate. He’d managed to eat some of the ravioli, though the rest of the meal seems more interesting when pushed around by his fork.

He’s never been good at waiting. Part of that comes from general impatience, while the rest stems from an innate need to act. A distraction would be useful right about now, but the only distraction immediately at hand is the apparent need to process that Steve has _feelings_ for him. For some time now. And they are apparently so genuine that they’ve triggered a biological response. Like a rash.

That’s funny. It’d be as if Steve has a Tony allergy.

But Steve wouldn’t find that description funny at all. He’d be offended, though not so much at the attempt at levity, but for its implication that Tony is something to be allergic to. Tony can picture Steve’s reaction so clearly: a knit of his brow, followed by a self-conscious pause where Steve reflects on his sense of humor, and then perhaps decides to let it go by changing the subject. Tony gets a lot of things wrong about Steve, but this image is crystal clear.

“If you’re not finishing that, I’ll take it,” Natasha says.

Tony looks up, and realizes that there are only two of them left, Bruce and Clint having made their exit when Tony was deep in thought. He shrugs and pushes the plate towards Natasha, who spears one of the pieces with her fork.

“You’ve been down to see Steve?” Natasha asks.

“Why can’t he just—” Tony waves a frustrated hand at Natasha.

“I’ve decided to take no offense,” Natasha says. “You’re welcome.”

“You know what I mean. You and Steve, you’re buddies, you’re tight, you’re the ultimate battle tag team. I mean, yes, all of us trust each other with our lives, but there’s extra special sauce between the two of you.”

Natasha hums neutrally.

“Not that you have to volunteer, of course,” Tony adds quickly, “but it’s just, it’s there, it should be an option.”

“It’s not only our choice that matters,” Natasha reminds him. “Steve’s matters as well.”

“Yeah.” Tony deflates. “Yeah, I know.”

Natasha knows about Steve’s feelings, doesn’t she? Team intel is her thing, so the safest assumption would be that she knows, and she is either too nice or too calculating to bring it up to Tony to his face.

Tony gets up, abandoning Natasha and her mysterious thoughts (plus the rest of dinner) to wander around the common area. The TV has no appeal, going to bed even less so, and though there are two dozen projects in the workshop that he could look at, he doesn’t have the mood for it. Anger, sadness and frustration are useful emotions to channel into work; this troubled restlessness is less so.

Tony lets his feet take him on a tour around the tower, traversing corridors and stairs, while bypassing the elevators. He goes to the labs, which are currently empty; the game floor, which is just depressing when there’s no one in it, especially that chair by the window that Steve likes to sit in when sketching; then down to the gym.

It’s stupid, he knows. Steve’s just downstairs and Tony literally saw him a couple of hours ago, but the Steve-shaped empty space feels massive. Enormous. Inescapable. It’s hard to remember that there was a time when Tony would automatically be on guard whenever he knew Steve was around.

The acute absence of Steve is especially apparent in the gym, which lights up when Tony steps into the room. He contemplates doing some pull-ups to burn off some energy, but finds himself heading over to the line of punching bags instead. Said bags are theoretically ordered by strength, but have in effect been separated into three classes (Thor, Steve, regular human people) and marked thusly by Steve’s paper doodles that are stuck above the frame.

Tony’s never gotten the hang of working out with the others, instead preferring to use his personal gear in the workshop. But he does come here sometimes for group training or sparring, the latter mostly with Natasha but very occasionally with Steve. In fact, Tony’s pretty sure that the mat folded up by the wall is the same one they used the other day when Steve showed him a couple of chokehold moves.

Gooseflesh rises along Tony’s arms at the memory. They’d grappled a little, with Tony typically annoyed at how much Steve had to hold back, and Steve exasperated at Tony’s annoyance. That dynamic’s familiar by now, for it rears its head in the field, during brainstorming and the occasional game night. But what Tony hadn’t noticed at the time (and hasn’t noticed for a long time) is the lowering of his own defenses, the ones he'd had his whole life to develop against unwanted alpha attention.

He'd let Steve try to hit him, grab him, and repeatedly throw him to the mat, which Steve did quite a few times. Tony of course returned the favor, and at one point got a really good uppercut that had Steve staggering backwards and put Tony in a full-on glow of pride for the rest of the day. Tony did all of this – he let Steve touch him and hold him down – and although he’d been irritated at Steve’s general ridiculousness, he’d not once felt threatened. Or afraid.

Tony wasn’t afraid earlier today, either, when faced with Steve at full rut.

It’s an interesting thought to gnaw at. Maybe it’s tied to how they’ve been working at their relationship so gradually that it no longer feels like work: nurturing respect and understanding of each other as possible. Tony doesn’t take Steve’s admonitions at their worst, and neither does Steve take Tony’s ribbing at face value.

That journey makes sense. At least, it seems to make sense to Tony as he looks back on it now. What makes less sense is that Steve’s apparently been on a different journey entirely, separate and invisible from what Tony thought was going on between them.

“ _Sir_ ,” JARVIS says.

“Yeah?” Tony says.

“ _Dr. Banner would like you to know that the first administration of the sedative appears to have worked, and Captain Rogers has finally fallen asleep._ ”

“Oh thank god. Are they gonna leave him in Cheryl?”

 _“Agent Barton is currently sitting with the Captain, though I’m also monitoring his vitals and will notify Dr. Banner or Dr. Cho of any changes._ ”

Tony nods. “Sounds good.”

“ _Might I suggest you get some rest, too, sir? Your room should be more comfortable._ ”

Tony starts and looks down at himself. While deep in thought he’d apparently decided to wrap his arms around Steve’s punching bag, which doesn’t even smell of Steve anymore. Just to check, Tony turns his face against the canvas and breathes in. Yep, only very mild Steve scent leftover.

With no one but JARVIS to judge him, Tony briefly squeezes the punching bag before letting go and leaving for some shut-eye.

+

Tony tries to sleep, honestly he does. He even manages a few hours here and there before giving up and deciding that something needs to be done.

The tower is quiet. It makes the heavy clanking of Tony’s suit seem even louder as he walks, though JARVIS assures him that the route he’s taking won’t bother the others.

When Tony makes it to the containment floor, Cheryl’s lights are dimmed, leaving only a low glow around its periphery. Tony approaches the glass panel, but is only halfway there when he sees that the cot is empty, and Steve is sprawled on the ground next to it, his head at an awkward angle.

“Steve?” Tony speeds up. “Steve! Shit—”

It seems way too long to open Cheryl’s door and get inside. Tony moves with his heartbeat thundering in his ears, and is crouched on the floor (as much as the suit allows) and has carefully turned Steve’s head to a more comfortable position before he belatedly notices that JARVIS has been trying to get his attention.

“J, vital signs,” Tony barks.

“ _I was about to say, sir_ ,” JARVIS says, somewhat tetchily. “ _Captain Rogers is stable_.”

“He’s on the floor!”

“ _He moved to the floor himself._ ”

“You mean he woke up?” Tony snaps. “He woke up and you didn’t tell Bruce?”

“ _I did tell Dr. Banner, who has already come to see him. Captain Rogers chose to move to the floor of his own accord, I assure you_.”

“Tony?” Steve opens his eyes groggily. “Wha…?”

“Why are you on the floor?” Tony says. “Besides giving me a fucking heart attack.”

Steve’s eyes struggle to focus, first on Tony’s helmet-covered face, and then the hand at his neck. Tony waits for his heartbeat to slow – at least, he thinks that’s why he’s slow to react when Steve turns his face against Tony’s gauntlet-covered hand, nosing the fingers and joints. Steve’s lids droop, drugged and disarming, as he rubs his face against the metal glove.

“Oh okay,” Tony says distantly. Steve turns onto his side facing Tony, and one of his hands finds the back of Tony’s calf to rub that, too. Tony can’t feel either touch through the suit but it’s kinda sweet in a literal he-and-the-suit-are-one kind of way. “The sedative only worked so far, huh.”

Steve’s eyes snap open at that. He inhales sharply, but Tony grabs him, both hands on his shoulders, before he can scramble away.

“Relax,” Tony says firmly, keeping his grip solid until Steve stops his wriggling. “Hi there, it’s me, I’m just checking up on you.”

Steve glares up at him from the floor. “You needed to come into the cell for that?”

“As a matter of fact, yes. What’s wrong with the cot? Need another one?”

Steve shrugs. He’s still grimy and feverish, but looks less like a zombie than he did earlier. He’s also changed into a different shirt and pants, though this pair is starting to get its own sweat patches in less-than-flattering spots. “Floor’s cooler.”

“JARVIS, bring the temperature down two degrees.” Tony reaches over and grabs the pillow and blanket from the cot, but just as he’s about to offer them, Steve’s pushed himself up into a sitting position and is eyeballing him witheringly. “Are you sulking now? Is that what you’re doing?”

“Tony,” Steve sighs.

“Steve. Wait, wait, check this out. New party trick.” Tony lifts himself up on his haunches and leans his weight back. The suit’s sitting mechanism clicks into place, locking the suit’s legs into a sitting position, as though there’s an invisible chair under him. Tony pumps both hands in the air in success.

Steve laughs. It’s a quick huff of a laugh, but still a real one, and accompanied by a genuine, sudden smile. Tony feels a burst of warmth through his chest and thinks, _huh_.

“Okay, that is neat,” Steve agrees.

“Yeah. Just gotta remember not to kick or cross either leg, then the balance goes off and whoopsy-daisy.”

“That actually happened to you in testing?”

“You can’t prove anything.”

“So you’re _not_ a proper science person who follows the scientific method by recording everything?”

“Who are you, the review panel for the American Materials Science Journal? Hush your mouth.”

Tony’s pretty sure this isn’t flirting. He’s an expert at flirting, thank you very much, and this isn’t that. It certainly doesn’t merit the way that Steve’s face goes soft and his smile lingers, which in turn has Tony’s stomach going topsy-turvy in a way it never did before. (Or never did so in such an obvious way.)

“Shouldn’t the serum prevent this from happening?” Tony says. “I mean, yes, we have already discussed this—”

Steve’s smile fades a little at the change of topic, but he says, “Have we? Have you?”

“Okay, I may have brought it up with Helen and Bruce, but they were more interested in finding a cure. Not that I _didn’t_ want to find you a cure, but, uh…” Tony clears his throat. “I just don’t get it, I guess. The serum’s supposed to optimize the whole body – hormones, homeostasis, everything – that it seems counterintuitive for it to cause this.”

“Maybe this _is_ the serum trying to fix it.”

“Trying to fix your severe case of horny?”

“A nicer person would not bring that up.”

“Sure, but I’m the one you want anyway.”

Steve stiffens. His eyes flicker over the helmet, automatically searching for a face to read before giving up. He swallows and shrugs, a brief rise and fall of his shoulders.

“Why, though?” Tony says.

“Why’s the serum’s overcompensating?”

“Why me.” Steve seems confused, so Tony adds, “Of, you know. Everyone else. Because you _could_ have anyone else and I’m – I’m quite – I know that I didn’t lead you on.”

“You didn’t,” Steve says. “You’ve just been you.”

“And that’s what you want?” Tony asks shrilly.

“Yes, Tony. And don’t say something rude as if it’s a moral failing to like you, because it’s not,” Steve says irritably.

“I wasn’t going to say that.”

“You’re thinking it.”

“Even if you’re right, which I’m not saying that you are, it could be an indicator that we’ve been doing okay on the friendship thing, but! If you got to know me even better, you’d see how much I’m not…” Tony trails off, struggling. “If you saw me up close I could disappoint you, is what I’m saying.”

“Maybe,” Steve concedes. “But it could just as easily go either way, as it is in any relationship anywhere.”

That’s true. Tony wants to argue against it but he can’t, because there is just as much a likelihood of Tony not being into Steve, as the other way round, if they give it a shot. Because Tony is honestly trying to imagine them giving it a shot, as improbable as the idea was a mere 24 hours ago.

Why was it improbable? Because Tony’s low-level attraction to Steve has been no more than cosmic background noise, and barely noticeable in the greater scheme of things. Now that he’s aware of Steve’s feelings, Tony has to confront that noise, and accommodate it, and realize that he doesn’t actually mind either thing (Steve’s feelings, or Tony’s reciprocal attraction, that is). He doesn’t _understand_ it, but it’s kind of… not unwanted.

“Why didn’t you ask me out?” Tony says.

Steve inclines his head, curious. “Would you have said yes?”

“Hell if I know. Would probably think it’s a joke.”

“There you go.”

“That’s not an answer!” Tony exclaims. “I know you said that you wanted to take things slow because you think you’re intense and will scare me off or whatever, but it’s – lately our whole lives have been big leaps one after another. And you – you tell people all the time about the dangers of waiting too long.”

Steve opts to stare at the floor instead of answering.

“Do as I say, not as I do?” Tony asks quietly. “Is that it?”

“I guess I’m just used to not getting what I want,” Steve says, his voice barely audible.

“Oh fuck you,” Tony says without venom. “Now _that’s_ a moral failing for you. Ask me now.”

Steve brings his scowl up to Tony’s faceplate. “What’s that?”

“Ask me out now,” Tony presses. “Promise me a good time, say that you’ll treat me right and be sweet on me, and spend time with me and—”

“Tony, your voice,” Steve says worriedly. “You sound—”

“I really like you, okay!” Tony yells. “This whole time I thought this, this thing in my gut was some stupid fucking desire for your approval, like I needed you tell me that I’m an okay person and worth liking, but it’s, it’s more than that. If I only needed Captain America’s approval, I wouldn’t be so goddamned worried about you right now – _you_ , as a person, a friend, maybe more. Steve, you’re right here but I – I miss you, and it hurts.”

“I don’t want you to hurt,” Steve says softly.

“I’m saying yes.” Tony takes a deep breath. His hands twitch restlessly inside the gauntlets, but right now all he dares do is reach out and put one of said hands on Steve’s knee. Even with the metal between them Steve lets out a low hiss, and his erection (that Tony’s been only mildly ignoring) stiffens further against Steve’s thigh.

“Steve,” Tony says firmly. “I’m saying not just for your sake, but for mine. If we’re going to be anything else to each other, you have to believe me now.”

“I, I don’t, it’s not that I don’t want to believe you,” Steve’s throat bobs as he swallows. “But this isn’t how we should’ve—”

“It’s not, but we’re flexible, yeah? And! You’re gonna make it up to me.”

“I am?”

“Yep! You’re going to take me out on proper dates, and tell me all the things you like about me while I do my best to return the favor—”

“’Favor’, wow. That’s totally convincing me.”

“See!” Tony points at Steve. “That right there is why you’re so… why I’m so…” He trails off helplessly. “Does any of that sound good to you?”

“It sounds fantastic,” Steve says, quiet and honest.

“Geez, Steve. I really want to get out of this suit.”

“ _You_ want?”

“It’s your call. It’s always been your call.”

Steve’s brow knits, as though he instinctually disagrees with that statement but can’t get a handle on why. It’s not even that Tony’s been trying to get Steve’s guard down specifically. All he wants is for Steve to understand that he doesn’t have to face all of this by himself. He has Tony, and his problems are Tony’s now, too.

Steve takes a breath. “Okay.”

The panels of the suit open so quickly it’s as though they’re tuned to Steve’s vocal commands instead of Tony’s. Tony’s urgency has him practically falling out of the suit and scrambling onto Steve’s lap, his hands reaching out to find purchase on Steve’s arms – whoa, he’s burning up – and squeeze firmly as if Tony’s the one who’s feverish and touch-starved.

Steve lets this happen. Or maybe it’s some short-circuit in his brain that has him not reacting to Tony’s dropping onto his lap beyond blinking owlishly up at him. There’s a minor short-circuit in Tony’s brain, too, because hey he’s never touched Steve like this before – arms pats and occasional shoulder bumps are nothing compared to suddenly being able to slide his hands over Steve’s ridiculous shoulders, and feeling the coiled strength there.

Steve looks at Tony’s arm on his shoulder, and then slowly turns back up at Tony’s face. His expression is strange and dumbfounded.

“Okay,” Tony says stupidly. For a second fear squeezes his chest, because what if this was a mistake, or Steve has second thoughts.

But then Steve’s pupils dilate, a shocking bloom of dark that’s the only warning Tony gets before the world tilts wildly.

A hand under Tony’s head stops him from getting a concussion on the floor. But Tony _is_ on the floor now, splayed out while the overheated mountain that is Steve is on top of him. Steve’s face is at Tony’s neck, huffing frantically as he scents him to his heart’s content, while Steve’s hands paw at him with some wild disbelief of Tony’s presence. Tony parts his legs to let Steve settle between them, and sure enough a very solid, very large, very ready cock rubs insistently at Tony’s inner seam.

“Huh,” Tony says. He’s into this. He’s really, honestly, tingly-between-his legs into this. The primal wildness is hot instead of scary, and sends a welcome flush across Tony’s skin.

Then Steve stops. With a visible rippling strain of muscle across his back, Steve lets out an almighty roar and pulls himself off of Tony, his eyes scrunched shut and his face in agony.

“No, no, no, no—” Tony grabs at Steve, twisting his fingers into Steve’s shirt and wrapping his legs around him to keep him close. “That’s mine, Steve!”

Steve pauses to heave for breath. “What?”

“This rut.” Tony cups Steve’s face, thumbs sweeping across Steve’s cheeks and he wills him to open his eyes. “It’s for me. Isn’t it?”

Steve grits his teeth but nods an admission.

“Are you listening, Steve?” Tony grins when Steve slowly opens his eyes. The struggle in his eyes is real, and Tony cannot look away even if he wanted to, which he doesn’t. “This rut is mine, and it would be mighty unfair of you to take it away from me.”

Steve’s gaze drops to Tony’s mouth, which is all the opening he needs. Tony curls his hands at the back of Steve’s neck and tugs, drawing Steve down, close enough that Tony can strain his neck upward to brush his mouth against Steve’s.

It’s a quick touch, their breaths mingling. Steve’s whole body shudders and then he’s pressing down to kiss Tony, hot and deep and so hard that Tony can only whimper his surprise. This right here is evidence of Steve’s passion – sure, it’s rut-enhanced, but it’s real, and for him, and Tony wants more of it.

He wants a _lot_ more of it.

Steve’s hands feel huge and somehow everywhere at once, touching Tony along his arms and torso and thighs, and setting Tony’s whole body alight. When Steve pushes his tongue into Tony’s mouth, Tony realizes that he’s also freaking ready for the other kinds of entry. He can feel himself getting wet in thick pulses, and just as he’s registering that there’s a sudden ripping sound down below – Steve tearing a clear opening through the inside of Tony’s sweatpants.

“Oh my god,” Tony breathes. “Yes, yes, right there—”

He cries out at the first touch of Steve’s fingers between his legs. Steve’s fingers sweep up along the juncture of Tony’s inner thigh, more curious than intending to be sexy – which is sexy in itself – before coming to a rest against Tony’s slick opening.

“Oh god,” Tony breathes. He hitches his hips up, which is enough for one of Steve’s fingertips to slip inside, easy as anything.

Steve draws back to stare at Tony in disbelief. “You’re…”

“Futurist, et cetera.” Tony gasps when that finger glides all the way in, one knuckle after the other. “Stretched myself some before I got here.”

Steve’s mouth quirks. “Seriously?”

“It was likely to happen. Also, please, I’ve seen your dick. A guy needs some warm up.”

Steve shakes his head and comes back down, this time to press searing kisses to Tony’s jaw and neck. “You’re really stubborn, you know that?”

“And you’re _into_ that, apparently,” Tony says. “So who the hell are you to complain now?”

Steve hums. “I can’t fault that logic.”

“Correct.”

Steve draws his tongue at the space under Tony’s ear, a languid movement that causes another eager flush of slick down below. Steve’s chest rumbles at the smell of it, but instead of continuing, he pulls his fingers out entirely and starts moving over to the cot. “Give me a sec. Condom.”

“You can’t catch anything and I’ve got the rest of it covered.”

Steve makes a face as he pulls a foil out of his bag.

“Fine,” Tony huffs. “But I’m just saying, my door’s wide open if you wanna.”

“Don’t—” Steve pauses, and takes a handful of steadying breaths through pursed lips. Once relatively calmed, he glares at Tony. “You know exactly what you’re doing to me.”

Tony can’t deny it. He can only grin as he props himself up onto his elbows to lose his shirt. The ruined pants can stay where they are as collateral damage. Meanwhile, Steve sheds his shirt and pants, too, and while Tony’s seen Steve’s near-nakedness in far more flattering conditions – poor guy still has a sickly sheen over him – there is glittering newness in his nudity today. It’s deliberate, _purposeful_ nudity, which makes all the difference. That’s Steve’s bare chest, waist and hips and thighs, plus a dick that’s been raring to go for more than a day now, the poor thing.

“Damn it.” Steve fumbles with the condom. He drops it, picks it up, and drops it again. “Fingers like sausages.”

“I got it.” Tony shimmies over to grab the fallen condom, pulling it all the way open and drawing it out. The next step is of course to put it on Steve’s dick, but as soon as Tony puts his hand on it, Steve makes this deep, shocked sound, as though the air’s punched right out of his lungs.

Tony looks up at Steve in alarm. Steve’s eyes are wide with desperation, and his cock spurts eagerly onto Tony’s hand.

“Count to ten,” Tony says quickly. He gets to work, pinching at the condom tip before sliding it neatly over the shaft. Meanwhile, Steve puts his teeth around his fist and growls into it, his shoulders hunched over as he tries to keep his body still.

“Okay, okay, we’re good to go.” Tony taps Steve’s elbow and quickly lies back down, his legs spread and knees lifted around Steve’s hips. “C’mon, let’s do this. Steve?”

“Yeah, I’m…” Steve’s shivering as he gets into position, exhausted from having to fight himself.

The bulbous head of his cock brushes over Tony’s opening, finding purchase. A nudge and it’s sliding in through slick, pushing the opening to tightness as it makes space for itself inside Tony’s body. Sure, Tony prepared for this with a couple of fingers and all, but it still takes him a moment to adjust and remember to breathe. That thing looked huge on the outside, but inside? Ho boy.

Then Steve says, shocked and dreamy, “Oh my god. Oh my god, Tony – Tony you feel incredible.”

“Thanks, I do yoga.” Tony shudders at Steve’s huffed laugh, which has his body vibrating across where they’re joined. Tony clings onto Steve’s arms and adjusts his hips to give Steve better access. “I’m here, go for it.”

Steve fucks him a little too quickly, a little too fiercely. Normally Tony would need more foreplay, but if ever he’d make an exception it’d definitely be today, with Steve’s whole body begging for relief and a handful of frustrated tears tracking down his cheeks. Tony won’t get off but he’s definitely getting something from watching Steve – poised, stoic, unruffled-in-anger Steve – lose his goddamned mind in Tony’s body.

It’s surreal. Tony’s never even hugged Steve properly before, yet here he is with Steve’s dick deep inside him, slamming home strong and frantic and with very little coordination, as if Steve’s some sad teenager who’s only just learned what that dick is for. Tony’s shivering, too, though not so much from an encroaching orgasm, but from the rush of how much Steve wants him.

Tony does his part. He drags his fingers down Steve’s arms, arches his back, and squeezes down around Steve’s length. At one point he strokes Steve’s face, which prompts Steve to nuzzle it and suck two of Tony’s fingers into his mouth, as though wanting as much of Tony’s taste in him as possible. As Steve’s movements get more frenzied, Tony finds purchase for his hands on Steve’s shoulders, hooks an ankle against Steve’s back, and holds on.

Tony’s definitely going to come hard later, but for now he’s too busy enjoying the rollickin’ ride that is one super soldier in the throes of a rut.

“Fuck,” Steve hisses. He’s close, each thrust landing with a smack against Tony’s ass, and barely a breath between them. Tony thanks his Iron Man career and everything associated with it for keeping him in shape, because he thinks he’d get whiplash from how hard Steve’s going for it.

The air is thick with musk and arousal. The thickness in him long ago stopped feeling like an intrusion, and is now just a gift, perfectly fitted and formed. Tony feels used and stretched in the best way, and doesn’t take his eyes off of Steve when he reaches his orgasm. Steve’s breathless grunts culminate in an ear-curdling cry that Tony would mock if it wasn’t heartrendingly genuine. Bliss, pain and relief flow over Steve’s face, followed by a whole-body shiver that has Steve’s teeth chattering.

When, at long last Steve regains himself, he looks down at Tony. Embarrassment flickers in his eyes, followed by surprise.

“What are you smiling at?” Steve asks, his voice sandpaper rough. He looks at Tony’s cock, then back up. “You didn’t come.”

“It’s stupid,” Tony says.

“Tell me anyway?” Steve says hopefully.

“It’s just… I know your life’s not been a cakewalk but you’ve always seemed to have everything under control. So it’s nice that I can take care of you. That’s all.”

“Setting aside that ‘useful’ doesn’t equal ‘important’, this is far from the only thing you’ve done for me.”

“Oh. Hmm.”

“You don’t believe me,” Steve says. It’s not a question. “It’s okay, I’ll work on that.”

“When you take me out?”

“Yes, I will.” Steve starts to pull out of Tony, wincing as he does. “Dinner, a show, or whatever else you like. But first, I think I need a condom change.”

Tony pushes himself up into a sitting position and rolls his shoulders. “Knot didn’t take?”

“Didn’t come out at all,” Steve says apologetically.

“Damn.” Tony sweeps a hand playfully across Steve’s strong thigh, and grins when he feels the muscles jump. “You need another one, huh?”

“I’m glad you’re upbeat about this. It’s rather – oh. God damn it.”

“What now?” Tony follows Steve’s dismayed look to the come-soiled condom he’d started to roll off his dick. It takes Tony a second to understand what he’s seeing, and when he does, he bursts out laughing. “Oh my god, Steve, you broke it! Helen made those custom for you, and you broke it!”

“Tony.”

“No latex on earth can stop super soldier swimmers on a mission!”

Steve barks an involuntary laugh, before quickly covering his mouth with his hand. It doesn’t matter, though, because Tony saw it.

“It isn’t funny,” Steve says. He grabs the small trashcan from underneath the cot to dispose of the broken condom, and he looks so serious about it that Tony has to poke at Steve’s calf with his toe.

“It’s a little funny,” Tony says.

“Only because this is an unusual situation,” Steve says.

“Exactly. C’mon.” Tony gets up, tattered sweatpants and all, and knee-waddles his way over to Steve. It’s not smooth, but he’s not trying to be smooth. He doesn’t _need_ to be smooth.

Steve’s making that face, the one that Tony used to mistake for disinterest but is actually Steve’s very specific brand of petulance. It’s enough of an invitation for Tony to nudge Steve to sit cross-legged on the floor, which in turn allows Tony the very awesome position of sitting astride Steve’s lap, his arms over Steve’s shoulders.

“Steve, buddy, pal—” Tony says.

“I’ve been inside you,” Steve mutters under his breath.

“So I can’t call you ‘buddy’ anymore? Fine.” Tony considers. “Boss?”

“God!” Steve gasp-laughs. “Tony, no.”

“Geez,” Tony says quietly. He puts a hand on Steve’s face, palm at his jaw and thumb brushing along the rise of his cheekbone. Steve makes a questioning sound, but otherwise lets Tony touch him and learn his face up close. Steve’s skin is still clammy, though no longer worryingly so; his lips are pale and his eyes bloodshot. Despite all of the above, Tony thinks Steve stunningly handsome just like this, when there’s an air of easy contentment about him (and not only because he’s gotten to come).

“Fever’s broken,” Tony says.

“Yes, I can feel it,” Steve says.

“Like the condom.” When Steve sighs, Tony presses on, “No, hear me out. That’s what a rut is for. I mean, yeah, we like to dress it up that it’s about intimacy and stress relief and purging our base urges, but it’s _really_ about propagation, and the fact that you’ve been suppressing your ruts for… how long has this been building up?”

“Not long,” Steve says shiftily.

“Right,” Tony says, filing that away for a later investigation. “So, from where I’m sitting, if you want to get this backed-up rut completely out of your system, you’re going to have to give it your all the old-fashioned way.”

“My all?”

“Yep.” Tony punctuates the statement with a kiss, landing soft and teasing onto Steve’s mouth. “Go bare, go deep, and try your level best to knock me up.”

“But you can’t—you said you’ve taken precautions, right?”

“Of course, but the rut doesn’t know that. So, how about it? We try a tupping, see how it goes?” Tony kisses Steve again, and tastes the _yes_ in his response.

Steve tilts his head up, drawing Tony in to deepen the kiss, which is followed by another, and another. The jaw-aching kisses of earlier were great, but these kisses draw pleasure in slow coils from low in Tony’s body, punctuated by the way that Steve’s slowly running his fingers over Tony’s lower back and waist.

Tony remembers being surprised by this – Steve’s admission, and the mere thought of being with Steve this way – but now all of it feels like it makes perfect sense, and that they were always heading in this trajectory.

“You think I wasn’t giving my all earlier?” Steve asks, his lips sliding hot over Tony’s.

“That was just urgency. Now you’ve got to mean it. You’ve got to—” Tony reaches back, finding one of Steve’s hands and guiding it down over Tony’s ass, “—make this yours.”

Steve inhales sharply and shudders.

“Feels good, doesn’t it?” Tony rolls his hips, pressing down to the familiar length underneath him. “You’re gonna have to fuck me until it takes. Until your knot takes, your come takes, all of it.”

They kiss until their breaths grow more labored and they’re rocking against each other. When the emptiness inside Tony gets too much, he rises off Steve’s lap and sees his own slick where it’d fallen onto Steve’s cock and inner thighs. Tony feels dizzy with it, and is clumsy when he reaches for the belt of his torn sweatpants.

“Leave it on,” Steve says quickly. “Uh, please? If you don’t mind.”

“Do not mind at all,” Tony says cheerfully.

Tony grabs the thick comforter from the cot and spreads it out on the floor before crawling on top of it. Steve takes the pillow and pushes it at Tony, insisting that Tony use it for padding. It’s a sweet gesture, and does not at all contradict Steve’s growing rumble when Tony goes into position, on his knees and bowed over, and head resting on his folded arms over the pillow.

This time when Steve enters him, it’s with a hitching push-in-and-drawing-back that lets him sink in in increments. Tony’s hole is only a little raw from the pounding earlier, nothing to worry about, and he hums encouragingly as Steve’s bare cock finds it way home.

This time Tony really feels it. The pure girth fits him so snugly, so perfectly, and with every hitch coaxes Tony’s opening to feed it more slick, which it does. Tony sighs and spreads his thighs, just in time for Steve’s hips to fit neatly into the place meant for him, his balls pressed against Tony’s perineum.

“Oh, Steve,” Tony breathes. “You gonna go for it? Gonna try to knock me up?

Steve bends over Tony, the warm breadth of him folding over Tony’s back. He circles his hips carefully, lighting up the tender center of Tony’s body. “You think you can take it?”

“You keep moving like that, I’m not gonna want anything else.”

“Good.”

Steve pulls out, pauses, and glides back in one smooth stroke to the base. He finds a new rhythm that’s strong and sure, though he adjusts it when Tony murmurs, “Slower but harder, getting quicker at the end like – yep, that’s it, that’s – _oh_ , oh my god that’s perfect, yes, yes, like that.”

It’s a good, rocking rhythm, and in no small part due to Steve’s quick study of what has Tony moaning and shaking underneath him. Steve’s having a huge cock would mean little if he weren’t a maestro at using it, where each thrust is purposeful in stimulating the aching, sensitive places inside Tony. Steve’s clever fingers work, too, finding the stiffened nubs of Tony’s nipples to play with in maddening counterpoint to the fucking going on elsewhere.

The pleasure builds, sweet and dizzying. Tony can feel his own slick traveling in fine rivulets down his inner thighs, which is a very sensible reaction to Steve’s fucking him with maddeningly patient panache.

How long do they go for it? Tony has no idea. All he knows is the pleasure buzzing through his body, and the expectation as he bows deeper into the classic presenting-for-a-knot position. Normally this position makes Tony uneasy, but Steve has proved himself an exception on so many levels, and not only because he’s been so determined to not hurt Tony despite suffering through a rut. Steve is a promise that should scare him, but doesn’t. Tony _wants._

They fuck, loud and lewd. Tony’s breathing hard and gasping, but even through that he can hear the slap of Steve’s thighs against his, and Steve’s murmured encouragements against his skin.

“Fuck, I need—” Tony swallows past his dry throat, “–Steve, I need your knot, I need to feel it – I need to be filled up—”

“It’s coming, it’s coming,” Steve says wetly against Tony’s back. “Need to get you ripe and ready first.”

“I am ready,” Tony gasps. “I am so, so, _so_ ready, just fucking breed me already, you’re supposed to be a stud, aren’t you, you’re meant to give it to me—”

“God, Tony,” Steve gasps shakily.

“You’re so deep already, Steve – you’re so deep, so perfect, you just need to let it go, fill me up—”

Steve makes a sound as he comes, but Tony barely hears it, too busy overwhelmed by the sudden rush of his own orgasm, pleasure cresting over him like a wave that goes on and on, and is punctuated by another wave when Steve’s knot thickens.

The fullness of the tie makes Tony keen, air whistling past his gritted teeth. He yelps again when Steve grabs his dick, fondling it quickly to tighten up his hole. The knot’s so huge that Tony can feel it adjust and settle inside him, making itself comfortable to the contours inside him. The feedback loop of pleasure has Tony light-headed and hyperaware of his whole body, wracked as it is with post-orgasmic shivers.

Tony vaguely registers being moved, though it’s only when he’s come back to himself that he realizes that he’s lying on his side, the pillow moved to under his head, and Steve wrapped up behind him. Steve’s dick pulses steadily, the knot fulfilled and doing its work in tandem with Tony’s willing body.

Tony smacks his dry lips together. “That went well.”

Steve grunts an agreement.

“Do you think I can take a nap, or do you want a running commentary on how it feels to be pumped full of—”

“Mercy, please,” Steve laughs, hoarse and breathless. One of his hands is on Tony’s stomach, drawing circles on his skin. “I’m done, I’m sure of it.”

“If you’re sure.” Tony closes his eyes and drifts for a while. He can feel his thoughts slowly unclog, and get more solid. “Do you think maybe like, the reason this rut got so bad is because your subconscious was picking it up from me, in my scent or whatever, that I’m… ready to reciprocate?”

“Are you still on about that?”

“Aren’t you curious?” Tony tries to turn to look at Steve, but with the knot locked the most he can do is get a glimpse of Steve’s bare shoulder. It’s not so bad, though, because Steve drops a lingering kiss onto Tony’s neck when he lies back down. “Because if it’s gonna be like this every time you get hit, well – I mean, sure, we’ll have fun, but what if it hits while we’re in a battle, or you’re stranded somewhere? If we know for sure that it’s because your body recognized mine, and it has what it needs, I’d feel better about it, I guess.”

Steve hums, and Tony can hear the smile in it. “You’ve solved one problem, and are already looking towards solving others.”

“Yeah?” Tony says, confused.

“That’s one of the many, _many_ reasons why I…” Steve trails off, and tightens his grip around Tony’s stomach. “Why it’s you, for me. I’m telling you.”

“Oh.” Tony is literally tied down to the man, and this is what has his face growing warm. “Okay.”

“We’ll be better prepared for next time,” Steve says.

“You don’t actually know that. You didn’t even tell anyone your ruts were getting worse. Why are you so bad at taking care of yourself?”

“Sorry.”

Steve _does_ sound sorry, which is at least something. But as Tony lies there and fumes through the afterglow, he decides that from now on it’s his job to make sure Steve doesn’t do anything stupid like that ever again. (And even if he does, Tony will be there to help and yell at him for it.)

+

Once they untie, they clean up in the bathroom module, change (Tony into a spare set of Steve’s clothes) and move onto a cot. There are two cots in the cell, but Tony makes plaintive noises at Steve until he acquiesces to sharing: two grown men smooshed together, Tony’s face tucked against Steve’s chest, because stubbornness wins out against comfort.

They sleep. Someone’s body temperature goes down from feverish to a cuddly ideal. (Steve.) Someone snores. (Tony.)

Tony wakes up to the noise of someone moving around nearby. As he cracks his eyes open, the aches all over his body remind him of the events of the night before. He also notes that he’s alone on the cot.

Steve’s moving around the cell, which has been cleaned up, evidence from last night mostly gone. Steve physically appears back to normal, too – healthy golden skin, strong posture, and that little wrinkle between his eyebrows as he squeezes the comforter into a trash bag. That’s Steve, who wants him, and has _feelings_ for him, and for whom Tony’s going to rearrange parts of his life to make more room for. A wave of fondness rushes over Tony, which in this case is almost as strong a cup of coffee in waking him up to full alertness.

Tony doesn’t move or make any noise, but Steve notices that he’s awake, and turns to him with a light, “Good morning.”

His tone is too light, too careful. A little distant, even, as though Steve’s hedging his bets.

Tony pushes himself up into a sitting position, and scratches idly at his chest. “Are you changing your mind?”

“What?” Steve says.

“What you promised me.” Tony stretches – his shoulders first, then his neck and arms. “Are you changing your mind about it?”

“You’re asking _me_ if I’m changing my mind.”

“Because I’m getting a vibe off of you, like you think everything I said yesterday was just to get you to knot me and get rid of the fever-rut the ‘easy’ way.”

“Uh.”

Tony sighs. “Great.”

“I know you wouldn’t do that,” Steve says patiently. “I ‘know’ that, logically. But I also know that I’m compromised where you’re concerned, and it’s possible that I wanted so badly for it to be real that I only _convinced_ myself that it was. So I thought I’d… get a lay of the land this morning.”

Annoying it may be, but that line of thinking tracks. Steve’s admission of Tony’s effect on him is another point to consider.

“Uh-oh, you’re upset,” Steve says. “That’s not good.”

“You think?” Tony says.

When Steve’s in a fever rut, he’s a pale, sweaty sack of pure sadness that Tony just wants to comfort and make feel better any way that he can. When Steve’s fully himself, as he is now, he’s a goddamned menace with a glint in his eye, and he comes over to the cot and goes onto his knees in front of Tony, which puts his eye-level below Tony’s (strategist!), and sets his warm palms on Tony’s knees (an effective strategist!).

“Perhaps I can make it up to you with a big breakfast,” Steve says. “The waffles you like?”

“Not for breakfast. _Someone_ says that ice-cream isn’t a breakfast food.”

“ _Someone_ is allowed to change his mind,” Steve replies easily. “What about it?”

“With blueberries. And coffee! So much coffee.”

“Will do.” Steve moves back and stands up, though he holds his hand out. Tony’s heart leaps at the gesture, though he thinks he keeps a very cool face as he accepts said hand and lets Steve pull him to his feet.

“But first,” Tony says, tightening his grip on Steve’s hand. “We’re going get you checked over with Helen.”

“It’s fine,” Steve says quickly, “I feel fine, everything’s back to normal—”

“Nope, no squirreling!” Tony finds his shoes, tightens up the drawstring on Steve’s pants with one hand, and proceeds to drag a sighing Steve out of the Cheryl, on the way to the lab and (symbolically, at least) the rest of their lives (maybe, probably, it’s too soon to say, but who knows).

**Author's Note:**

> [Tumblr post for this fic!](https://no-gorms.tumblr.com/post/614265379358932992/a-contribution-stuck-in-a-12998-words-by)
> 
> Many thanks to flyingcatstiel for the lookover. Remaining mistakes are my own, feel free to let me know about them in the comments or via my tumblr.


End file.
